Concept Feasibility and Predicted Behavior of Mining a Rock Tower with Drill-And-Blast Undermining Using Dynamic Three-Dimensional Discontinuum Numerical Models
Bibliographic record
Abstract
ABSTRACT: The safety and efficacy of a proposed novel mining method - felling a mineralized rock tower away from an adjacent river and towards an existing open pit using a wedge-shaped "key-cut" blast pattern and post-split hinge – was analyzed by integrating site-specific and site-adjacent data to develop a into a dynamic three-dimensional discrete element method numerical model. These data included historic laboratory testing and geomechanical core logging from the adjacent open pit, Lidar scans and geomechanical spot mapping of the rock tower, local signature blast seismic data, and proposed blast-pattern. Static and dynamic model stages were run to assess the pre-blast, syn-blast, and post-blast deformation of the mineralized rock tower. Model sensitivities to mesh size, dynamic time-step, block size, and joint strength were assessed. Ultimately, model results indicated that the proposed mining method would likely result in 97 percent retention of the blasted material within the existing open-pit, and only 3 percent of material would be cast towards the adjacent river. 1. INTRODUCTION The Dragon's Tooth rock tower is located near the base of an existing open pit at Mine A along the bank of a perennial river (Figure 1). The rock tower extends 50 meters (m) vertically above the open pit bottom and ranges in diameter from approximately 20 m at the crown to approximately 40 m at its basal contact with the adjacent open pit. The Dragon's Tooth and underlying material contain gold ore but were not mined with the completion of the open pit due to limited safe access for conventional open-pit mining equipment. Successful mining of the Dragon's Tooth depends on limiting the casting and sliding of large blocks (i.e., blocks that require re-blasting) towards the river and the volume of fill required for access. This will afford more ore recovery and avoid blocking the river for a prolonged period. Mine A contacted Dyno Consult (DC) to develop a method to safely collapse the mineralized tower away from the river. DC developed a wedge-shaped "key-cut" blast pattern (Figure 2) and post-split hinge to topple the rock tower towards the open pit. The safety and efficacy of the proposed method was assessed using numerical models.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".